The present invention relates to an electrical connector to be connected to a flat conductive member.
Patent Reference has disclosed a conventional electrical connector (a connector) to be connected to a flat conductive member. According to Patent Reference, the conventional electrical connector includes a housing for receiving the flat conductive member such as a flexible printed circuit board (FPC) and a flexible flat cable (FFC), a plurality of terminals, and an actuator attached to the housing.
The terminals include a plurality of first terminals and a plurality of second terminals. Each of the first terminals and the second terminals is made from a metal plate by punching into an H-character shape substantially so as to maintain a plate surface of the metal plate. The terminals are pressed into and held in the housing so that the plate surfaces thereof are parallel to each other. The actuator is capable of rotating around a shaft portion thereof between an open position and a closed position. The actuator allows the flat conductive member to be inserted into the housing at the open position and allows a contact portion of the terminal to keep contacting with the flat conductive member inserted, with a contact pressure at the closed position.    Patent Reference: Japanese Patent Publication No. 2007-287398
In the conventional electrical connector, one of the first terminal and the second terminal, for example, the second terminal, includes an upper arm portion and a lower arm portion extending in a direction that the flat conductive member is inserted (an insertion direction). The second terminal further includes a combining portion combining the upper arm portion and the lower arm portion. The upper arm portion and the lower arm portion include a combined area, that is, an area thereof combined to the combining portion, respectively.
The lower arm portion includes a cable supporting portion supporting the flat conductive member from a lower direction. The cable supporting portion is situated at one end of the lower arm portion in the insertion direction. The lower arm portion further includes a connecting portion (a tail portion) to be soldered to a circuit board at other end thereof in the insertion direction. The upper arm portion includes a contact portion for contacting with the flat conductive member at one end thereof and a lever portion at other end thereof for controlling the shaft portion of the actuator not to move in an upper direction.
When the actuator rotates from the open position to the closed position after the flat conductive member is inserted into the housing, the shaft portion having an oval cross-sectional surface pushes the lever portion in the upper direction. Further, the upper arm portion rotates like a lever, as well as the combining portion deforms elastically. As a result, the contact portion of the upper arm portion moves in the lower direction, thereby contacting with a conductive line provided on an upper surface of the flat conductive member with the contact pressure. The first terminal has a similar configuration with the second terminal, except the connecting portion is provided at the end where the cable supporting portion is situated.
The housing includes a first terminal holding recess portion and a second terminal holding recess portion or terminal holding recess portions having a slit shape. The first terminal holding recess portion holds the first terminal and the second terminal holding recess portion holds the second terminal by holding the plate surfaces of the terminals, respectively.
The second terminal holding recess portion includes a narrower portion corresponding to a portion situated nearer the contact portion in relation to the combining portion of the upper arm portion, a portion situated nearer the cable supporting portion in relation to the combining portion of the lower arm portion, and the combining portion of the second terminal, respectively. The narrower portion has a width in a thickness direction of the terminal close to a thickness of the terminal. Accordingly, a width of a space generated between the plate surface of the terminal and an inner surface of the terminal holding recess portion is extremely narrow or almost zero. The narrower portion controls a shift of the second terminal in the thickness direction, thereby the second terminal is held in a proper position.
In addition, the second terminal holding recess portion includes a wider portion and a cut portion at a remaining area or an area corresponding to an area from a portion next to the connecting portion to the combined area of the upper arm portion, through the combining portion of the terminal. A width of the wider portion is sufficiently wider than the thickness of the terminal. Accordingly, at the wider portion, the second terminal holding recess portion has a space against the terminal wider than the space at the narrower portion. Consequently, the second terminal holding recess portion obtains a space with a certain width between the plate surface of the second terminal and the inner surface of the wider portion thereof, facing the plate surface of the second terminal. Further, the cut portion penetrates both side walls of the second terminal holding recess portion, thus a space is provided between the terminal and the second terminal holding recess portion at the cut portion as well.
Accordingly, when the connecting portion of the lower arm portion is soldered to the circuit board and flux flows up in the narrower portion along the plate surface of the connecting portion situated in the narrower portion due to a capillary action, the flux does not flow into the wider portion since there is the space wide enough to stop the capillary action, between the inner surface of the wider portion and the plate surface of the terminal. Thereby, it is possible to prevent the flux from flowing into further.
In the conventional connector in Patent Reference, it is possible to prevent the flux from flowing up. Accordingly, it is possible to maintain the upper arm portion movable by preventing the flux from reaching the upper arm portion through the combining portion. The first terminal holding recess portion for holding the first terminal has a similar configuration with the second terminal holding recess portion essentially.
As described later, it is preferable that the flux does not flow up thoroughly, since the terminal may receive a negative effect as the flux flows up. Therefore, for the purpose of preventing the flux from flowing up, it is preferable that the wider portion is also provided at an area corresponding to the connecting portion, that is, a portion soldered to the circuit board in order to obtain a space around the connecting portion.
When the wider portion is provided at the area corresponding to the connecting portion, the terminal is held with two narrow portions only, that is, the portion situated nearer the contact portion in relation to the combined area of the upper arm portion, and the portion situated nearer the cable supporting portion in relation to the combined area of the lower arm portion. Accordingly, the terminal tends to easily shift in the thickness direction thereof. As a result, the terminal tends to have an unstable position in the thickness direction thereof, at the wider portion.
For example, when the terminal is pressed into the terminal holding recess portion with a slight shift from a proper position, or when the terminal has a deformation such as a warpage, the wider portion is wide enough to allow the terminal to remain in the shifted position or to keep the deformation thereof in the wider portion. As a result, in the wider portion, for example, it is possible for the terminal to obtain a declination or a deformation as a whole in the thickness direction thereof (a waggle) and a deformation in which the upper arm portion and the lower arm portion deform apart from each other in the thickness direction thereof (a buckle).
As described above, when the terminal deforms in the thickness direction thereof, one of the plate surfaces of the terminals can contact with the inner surface of the wider portion. Therefore, in a case that the terminal has the waggle or the buckle, the flux provided by soldering the connecting portion can flow into the wider portion, along the plate surface contacting with the inner surface of the wider portion though the wider portion is provided around the connecting portion.
The flux flowing into the wider portion can reach the upper arm portion through the combining portion eventually. Accordingly, the upper arm portion can be adhered to an inner surface of the terminal holding recess portion with the flux, so that mobility of the upper arm portion can be seriously suffered. Moreover, when the flux reaches the contact portion of the upper arm portion, an electrical contact failure can occur between the contact portion and the flat conductive member.
In view of the problems described above, an object of the present invention is to provide an electrical connector for a flat conductive member, capable of preventing the flux from flowing up by controlling a shift of a terminal in a thickness direction, as well as providing a wider portion corresponding to where a connecting portion is provided.
Further objects and advantages of the invention will be apparent from the following description of the invention.